Locking mechanism



March 31, 1931. H JUNGHANS LOCKING MECHANISM Filed Aug. 6. 1928 l nvenlor;

HeZ'rnuZ tfun ghans y M Patented Mar. 31, 1931 UNITED STATES HELMUT JUNGHANS, OF SGHRAMIBERG, GERMANY LOCKIN G MECHANISM Application filed August 6, 1928, Serial No. 297,902, and in Germany April 21, 1928.

My invention relates to locking mechanisms and more particularly to an improved noiseless ratchet.

In the ratchets as hitherto constructed a clicking noise is produced during the winding-up operation mainly due to the pawl engaging in the spaces of the teeth of the ratchet wheel and striking upon the bottom of the space.

The object of my invention is to remedy this defect and to produce a ratchet which will make no noise when being wound up. IVith this object in view I construct the ratchet in a manner that the pawl will be held out of engagement with the ratchet wheel during the rotation of the latter for the winding-up purpose, and will automatically again engage therewith at the end of the winding-up operation.

To this end I provide laterally on the ratchet wheel a resilient cam-disk in frictional engagement therewith and I further provide a somewhat triangular recess in the said camdisk and a fixed lateral pin in the pawl adapted to engage in and cooperate with the said recess as will be described more in detail in the following specification, two edges of the recess only co-operating with the pin, the one for the purpose of disengaging the pawl from the ratchet wheel at the beginning of the winding-up operation and the other one for the end of the winding-up operation.

I will now proceed to describe my invention more in detail in connection with the embodiment thereof illustrated somewhat diagrammatically on the accompanying drawings, it being intended and understood that the invention which is of wide and general application, is illustrated by, but not limited to the embodiment thereof so illustrated and described.

In the accompanying drawings forming a part of this specification and showing for 4a purposes of exemplification, a preferred form and manner in which the invention may be embodied and practised Figure 1 shows in front view or elevation a ratchet constructed according to the present invention, and Figure 2 is an end view thereof.

In the embodiment shown the ratchet wheel a is providedwith a lateraldisk-like projection 22 rigidlyconnected or integral with the wheel a. Mounted on the projection 7) is a yielding or resilient cam-disk 0 which is slightly bent out of its plane and adapted to freely revolve about the projection 5 while frictionally contacting with the ratchet wheel and a fixing disk d attached to the projection so that the cam-disk fits snugly'between the wheel a and the disk d. The cam end of the disk 0 projecting beyond the toothed periphery of the wheel a is re cessed to form a somewhat triangular opening a and a pin firmly connected with the pawl g is adapted to freely engage in the opening or recess 6 when the pawl g occupies its locking position as will be seen in Figure 1, a spring it being provided to constantly exert a pressure on the pawl, as usually in ratchets, in order to hold the pawl in looking position. The two edges or sides 2' and 7c of the recess 6 are shaped and adapted to bring about disengagement and reengagement of the pawl with respect to the ratchet wheel, respectively, as will be explained hereinafter.

The operation of the improved ratchet wheel is as follows l/Vhen the wheel is wound up the cam disk 0 will first move together with the wheel due to frictional. contact, while the pawl g is gradually lifted by the tooth f, the Wheel with which it is in contact for the time being, and thereupon, that is when the wheel has moved for the peripheral length of one tooth, the pawl will not descend and engage in the next space under the pressure of the spring h but will be further lifted a littleand retained in raised position by. the

guiding edge 2' of the recess 6 of the camdisk 0. This action is accomplished by the pin of the pawl sliding on the edge 5 up to the end thereof where the recess is shaped to form a kind of a seat for the pin to abut against and to rest therein until the winding-up operation is finished. Thus during the winding-up operation the cam-disk 0 will be arrested and locked by the pawl through the recess 6 thereof co-operating with the pin of the pawl and the latter will be locked in raised position, againstthe action of its spring h, by the edge i'o'f therecess particularly shaped for the purpose.

As soon as the winding-up operation is finished and the ratchet wheelceases'to "re- Volve, the cam-disk will return to its normal or original position, due to the action ofthe spring h, and the .pin- 7 will engage theguiding side 70 which coacts with the spring h to causethe pawl to catchIinto a dwell or space between two successive teeth so as to re-occupy a position as shown in Figure 1.

It will be seen'that' by positively guiding the pawl in the manner herein set forth a noiseless ratchet will be produced in a practically simple-and efiicient manner. t will beevident, however, that my invention, which still being adhered to in itsmain essentials maybe va-ried'and adapted in many ways according to requirements desired or most suitable under'dilierent circumstances.

l. Airatchet mechanismparticularly fora winding up operation comprising a ratchet wheel,a pawl adapted to'cooperate with'the said wheel, a spring mounted tohold the pawl in engaged position relative tothe wheel, a lateral pinzfixed in said pawl, and a cam disk mounted adjacent to and laterally of'the said wheel to be free to revolve with the latter due to frictional connection and adapted to'be arrested while the wheel continues'to revolve, said cam-disk having a recess or opening therein which is approximatelytriangular in shape and in which the "pin engages and said disk being provided with a notch merging in said recess in which the pinengages to maintainthe pawl out of contact with the ratchet wheel durin'g the winding up operation and also having aguiding side for the'pin 'tojpe'rmit :the pawl to contact "with the ratchet wheel.

2. -A ratchet'm'echanism particularly for a winding up operation comprising a ratchet wheel, a pawladapted'to cooperate with the said wheel, a spring mounted to hold the pawl'i'n engaged position relative to the wheel, a'lat'eral pin'fixed in said pawl, and-a camdiskhaving'a projecting cam end and mountedadja'centto and laterally ofthe-said wheel to be free to revolve together 'with'the latter due'to frictional'connecti'onand adapted to be arrested while the wheel continues to revolve, said cam end'of the c'am diskhaving 9. 

